1. Field of the Invention
The present invention relates to a substrate treatment apparatus and a substrate treatment method for removing a resist from a substrate such as a semiconductor wafer.
2. Description of Related Art
In production processes for semiconductor devices, liquid crystal display devices and the like, a substrate treatment apparatus of a single substrate treatment type adapted to treat a single substrate at a time is often used for treating a substrate front surface with a treatment liquid. The substrate treatment apparatus of the single substrate treatment type includes a spin chuck which generally horizontally holds and rotates the substrate, and a nozzle which spouts the treatment liquid toward the front surface of the substrate rotated by the spin chuck.
A semiconductor device production process, for example, includes the step of locally implanting an impurity such as phosphorus, arsenic or boron (ions) into a major surface (front surface) of a semiconductor wafer (hereinafter referred to simply as “wafer”). In order to prevent the ion implantation in an unnecessary portion of the wafer, a resist pattern of a photosensitive resin is formed on the front surface of the wafer to mask the unnecessary portion of the wafer with the resist in this step. After the ion implantation, the resist pattern formed on the front surface of the wafer becomes unnecessary and, therefore, a resist removing process is performed for removing the unnecessary resist.
In a typical example of the resist removing process, the front surface of the wafer is irradiated with oxygen plasma to ash the resist on the front surface of the wafer. Then, a chemical liquid such as a sulfuric acid/hydrogen peroxide mixture is supplied to the front surface of the wafer to remove the ashed resist. Thus, the resist is removed from the front surface of the wafer. However, the irradiation with the oxygen plasma for the ashing of the resist damages a portion of the front surface of the wafer uncovered with the resist (e.g., an oxide film exposed from the resist pattern).
In another example of the resist removing process, sulfuric acid ozone prepared by dissolving ozone gas in sulfuric acid (sulfuric acid solution) is supplied for lifting off the resist from the front surface of the wafer without the ashing. The resist lift-off process using the sulfuric acid ozone may be performed, for example, by means of a batch type apparatus disclosed in US2008/006295A1.